Presenter:

Marek Tylutki(Department of Applied Physics, Aalto University)

Authors:

Marek Tylutki(Department of Applied Physics, Aalto University)

Päivi Törmä(Department of Applied Physics, Aalto University)

We study the Hubbard model with spin imbalance in multiband systems, particularly the Lieb lattice, which features a flat band. The flat band is known to enhance superfluidity due to a diverging density of states. We obtain a phase diagrams of this system using a BCS (mean field) theory, and we identify a variety of phases. Apart from the standard BCS and normal states, we observe the Fulde-Ferrell-Larkin-Ovchinnikov type phases with space-dependent pairing function. We also find a thermodynamically stable Sarma phase, where the imbalance coexists with a spatially uniform order parameter.